Differential thermal analysis of fluoroelastomer systems

Differential thermal analysis curves of diamine‐, peroxide‐, and magnesium oxidetreated vinylidene fluoride‐perfluoropropene copolymer show that crosslinking processes take place at ca. 140–200°C. A good state of cure is attained with amines (biscinnamylidene hexamethylenediamine) and benzoyl peroxide, although probably by different processes; magnesium oxide is much less effective. The vulcanized materials are less thermally stable than the untreated fluoroelastomer, as indicated by the lowered onset of decomposition. The effect is more significant in the amine‐cured materials; it can be deducted that amines, besides crosslinking the polymer, also modify it substantially, most likely by the formation of unsaturated centers.